Denture



Patented May 25, ts: I l '2,08l,392

. UNITED srA'rEs PATENT oFFlcl:

j "l linriiluc' G. Touced r zl ifil N. Y., I

Consolidated Oar-Heating Company, Inc.,

Albany, N. 2., a corporation of New York No ill-owing. Application August 8, 1934 Serial No. 738,935 I 4 Claims. (Cl. 32-2) This invention relates to metallurgy, particu- Although a superior alloy may be made for the larly to a metallic alloy, and more especially to purposes stated by alloying cobalt and chromium a metal alloy particularly adapted for the maksolely, I preferto make use of improving metals.

I ing of prosthetic articles. As stated in the patent previously referred to,

5 Heretofore, it has been proposed to cast prosthe melting point of, the alloy is t best very 5 thetic articles, such as dentures, from an alloy high. Applicant has discovered that by substicomposed of cobalt and chromium, perhaps with tuting molybdenum for tungsten a substantial the addition of improving metals, or from an lowering of the melting point takes place. The alloy composed largely of cobalt and chromium molybdenum app to e in p u m t combined with tungsten and titanium as diswhen pre en t but from ca Well 10 closed in my prior Patent #1,961,626, granted be used, thus securing either more or less of the June 5, 1934. eflect desired without seriously affecting the basic Continued investigation has shown that the p p r alloy dealt with in Patent #1,961,626 may have e owe of t e me n poi t o the oy its properties substantially improved by proper y the diti n of molybdenum i especially 15 modifications. It is with these modifications slra e wh n u g th alloy f r th purp of that the present application deals. making dentures because both chromium and It has been found that the ratio of the cobalt cob t seem to ave a marked afl ty for re acto the chromium in this alloy is a critical one, torie at i h emp s and to have a tendand that deviation from an optimum ratio, on ency to react with the investment material of the either side, results in an impairment of the demeld- This undesirable 'aetien and affinity s sirable properties. This optimum ratio applimin z y k pin h m lti Point f h cant has established to be 1 part of chromium to alloy as low as Possible, which is done y the 2.3 parts of cobalt. I dition of molybdenum.

Up to about of chromium the chromium Further, y the use Of the c a t nd chromium 5 additions to the cobalt result in a structure which in a ratio of t0 the amount 0f titanium used is homogeneous or single phase. When more y be substantially w pp n finds than 39% of chromium is added, a heterogeneous that with this ratio a superior alloy may be made or two phase system results. This two phase using titanium at approximately from %-2%- 30 system is made up of a hard-and a soft constits In adding the titanium, manganese ta u 30 uent. As a result, any attempt to polish th titanium carbide, copper titanium, or term titwo phase alloy causes relief etching, the ha d tanium may be used. Experience has shown the constituent not wearing down to the same degree manganese titanil-lm to be Preferable because 0! asthe soft one. The metal, therefore,'will not it action i de di a d de itri yin the take the bright, lustrous polish desired. Furalloy. It gen a y ta s one part of tita um 35 ther, as a result of this hard constituent the alloy to two Parts O manganese- This method of is very brittle, a feature definitely not desired. trodlleing h titanium is also an improvement In fact, the brittleness renders the use of the Over e method Previously disclosed and is 01 alloy as a denture undesirable because of the very considerable advantage as t al ows the 40 greatpossibility of breakage with consequent inalloy o be manipulated W h x r i in u h 40 convenience to the user and necessity for replaceextreme preeeiltlons would Otherwise be ment. On the other hand, the alloys containing 'y On account of the extreme susceptibility to less than 30% of chromium while homogeneous atmosph Conditions O e alley of c um single phase alloys, are decidedly inferior to the a c b solely With e formation o Oxides alloy containing the optimum proportionsin and nitrides therein which have a deleterious in- 45 mechanical and physical properties and also in fluence upon the alloy. corrosion resistance. As stated in my prior patent hereinbelore're- The most desirable alloy, therefore, is as apferred to, I prefer to add a small amount of sllipiicant has found, one containing the maximum con to the alloy as this increases the fluidity and 60 amount of chromium possible without exceeding causes it -to flow so much more readily, especially the limit of the single phase solid solution type when used for casting dentures. I find that I alloy. When such an alloy is formed, its charcan well use the silicon from about 0.2 to 1%. acteristics are what might be called remark- The alloy specified by applicant, made of coable, from the mechanical, physical and chemical balt and chromium, molybdenum and titanium,

65 standpolnts. and in which the proportions of cobalt to chromium is 2.3 to 1, and in which the proportion does not vary more than from 2.4-1 to 2.2-1 is remarkably resistant to corrosion; is easily poliahed, and takes an exceptional finish; the color is somewhat akin tobut not as white as platinum; it is entirely suitable for casting; has a hardness appropriate for a denture; has a high tensile strength; is free from objectionable brittleness; has a low coefllcient of expansion; and may be soldered and welded by the use of the ordinary methods, in which hard solder is used by niachanical dentists.

What I claim as new and desire to secure by Letters Patent 0! the United States, is:

1. A denture formed of an alloy of cobalt and chromium containing 1 part of chromium to 2.2 to 2.4 parts of cobalt.

2. A denture formed of an alloy oi chromium and cobalt in which the proportions are substantially 1 to 2.33 and in which there is from 1 to 8% molybdenum; and titanium from 0.2 to 2%.

3. A denture formed of an alloy oi. chromium and cobalt in which the proportions aresubstan- Y tially 1 to 2.33 and in which there lsi'rom' 1 to and which also contains molybdenum from more than 3% to about 8% whereby the melting point of the composition for casting purposes is substantially lowered and the shrinkage in solidifying thereby reduced.

ENRIQUE G. TOUCEDA. 

